Mary Clerkin Higgins
Painted (stained) glass is, traditionally, an architectural medium. In its original location, it is almost always an integral part of the fabric of a building, functioning not only as a work of art, but also as a screen, letting in light and keeping out the elements. It is different than sculpture or painting, in that one does not have the option of leaving it in its damaged state on philosophical or aesthetic grounds–a hole exists which must be filled, (to prevent birds, rain, light and other unwanted environmental factors from entering the building.) For architectural glass the problem then becomes, not will the hole be filled, but rather, how will the hole be filled.
A rock or hailstone are not the only causes of loss; at times, the glass restorer may be the culprit. Past restoration practice often resulted in the removal of glass with even one break, a decision motivated by the fact that cracks leak and architectural glass must be waterproof. Still, even the retention of the original glass and the insertion of a repair lead is a loss to the stained glass, since the integrity of the graphic of the lead network is lost, usually along with some of the glass. A significant part of any present-day restoration entails determining what glass is original, what has been inserted, and what the original lead lines were.
These practical restoration considerations continue to dominate the field of stained glass. While there has been more exposure to and acceptance of basic conservation principles by some studios, there is still much to be done. New materials, and an adherence to fundamental conservation philosophy, have radically changed the possibilities of museum conservation of stained glass, and they are just beginning to influence architectural glass as well. This must inevitably cause are evaluation of compensation issues and options in the field.